ItalianoEnglish
Put down the ramps, the belts, the fans and the balloons, press start, and watch whether the ball reaches the basket. One tap picks a part up, one tap puts it down, one more turns it: nothing to drag around under your own thumb.
Pick a part up and the line appears: nothing is built above it, that is the drop. 
The machine worked, and the bench warmed up. 
The workbench: every part, nothing to win.
What it does
- Eight parts, not thirty: ramp, bumper, belt, trampoline, seesaw, fan, balloon and pin. A game like this lives on how many combinations there are between two parts, not on how many parts there are.
- Twelve machines in the order they teach, plus the workbench: every part, no basket, nothing to win — that is where you find out what a fan does to a balloon.
- The same machine does the same thing, every time: the physics is repeatable, and a contraption that works every other time is not a contraption.
- The bench warms up as the ball gets near the basket: even a machine that did not work tells you how close it came.
- In English and Italian, following the phone's language.
Every machine is checked before it ships
A level is drawn by hand, but its solution is found by a program: it tries every position and every rotation of every part, and then searches again for the solution with the most room around it — the first one it finds is nearly always a glancing hit off the corner of a beam, which works and which nobody would ever have meant. Then it moves each part a square and turns it a notch, and demands that it still works.
Your data stays yours
Contraption asks for no permissions beyond the ad network, the vibrator and keeping the screen awake while you watch the machine run. No account, no online gallery, no leaderboards — that would be a server, and we do not have one. The machines you got working stay on the phone.
How it is paid for
One banner anchored at the bottom, and that is all: no ads inside the app, no subscription, no feature held hostage.